\(\Leftrightarrow23\left(14-4\right)-4\left(x+5\right)=25\)

\(\Leftrightarrow230-25=4\left(x+5\right)\)

\(\Leftrightarrow205=4x+20\)\(\Leftrightarrow4x=185\)\(\Leftrightarrow x=\dfrac{185}{4}\)

\(14.23+4.23-4.\left(x+5\right)=30\)

<=>\(23\left(14+4\right)-4\left(x+5\right)=30\)

<=> \(23.18-4\left(x+5\right)=30\)

<=> \(414-4\left(x+5\right)=30\)

<=> \(-4\left(x+5\right)=-384\)

<=> \(x+5=96\)

<=> \(x=91\)

Vậy x= 91

a)x+2=-5

x=-5-2

x=-7

b)2x-30=14

2x=14+30

2x=44

x=44/2

x=22

c)14*23-4*23-4*(x+5)=30

(14-4)*23-4*(x+5)=30

10*23-4*(x+5)=30

230-4*(x+5)=30

4*(x+5)=230-30

4*(x+5)=200

x+5=200/4

x+5=50

x=50-5

x=45

d)3^x/3^5=45/5

3^x-5=9

3^x-5=3^2

x-5=2

x=2+5

x=7

2)x=2+2+0+1+0+2+0+1+1=9;y=9;z=9

a)x+2=-5

x=-5-2

x=-7

b)2x-30=-14

2x=-14+30

2x=16

x=16:2

x=8

c)14.23-4.23-4(x+5)=30

23(14-4)-4(x+5)=30

23.10-4(x+5)=30

230-4(x+5)=30

4(x+5)=230-30

4(x+5)=200

x+5=200:4

x+5=50

x=50-5

x=45

d)3^x:3⁵=45:5

3^x:3⁵=9

3^x:3⁵=3²

x:5=2

x=2.5

x=10

2)z=3

câu a: x=-7

câu b:x=8

câu c:không có giá trị

câu d:x=7

Bài 4:

\(a,2^{30}=\left(2^3\right)^{10}=8^{10};3^{20}=\left(3^2\right)^{10}=9^{10}\\ Vì:8^{10}< 9^{10}\left(Vì:8< 9\right)\Rightarrow2^{30}< 3^{20}\\ b,9^{10}.27^5=\left(3^2\right)^{10}.\left(3^3\right)^5=3^{20}.3^{15}=3^{35}\\ 243^7=\left(3^5\right)^7=3^{35}\\ Vì:3^{35}=3^{35}\Rightarrow243^7=9^{10}.27^5\)

Bài 5:

100< 5^2x-3 < 59

Đề vầy hả em?

a ) x=3

b)2x=-14+30

=>2x=16

=>x=8

c)=(14-4).23-4(x+5)=30

=>230-4(x+5)=30

=>4(x+5)==30+230=260

=>x+5=260/4=65

=>x=65-5=60

d)=\(3^x\):\(3^5\)=9

=>3^x=9.3^5=2187

=>x=7

a, x = 28

b, x = 1

c, x = 24

d, x = 3

a) 2/5+9/5=11/5

b) 15/45+25/30=7/6

c) 28/32+45/72=3/2

d) 8/28+5/30=19/42

bài 2

a) x - 4/5 =4/5 + (3/7+3/5)

x-4/5=4/5+36/35

x-4/5=64/35

x=64/35+4/5

x=92/35

b) x-7/35=4/5

x=4/5+7/35

x=1

nhớ tk m nhé

a = 18/5

b = 3/9 + 5/6 = 6/18 + 25/18  = 31/18

c = 7/8 + 5/8 = 12/8

d = 4/14 + 1/6 = 14/42 + 7/42 = 21/42 -= 7/14

b2

x - 4/5 = 4.5 + ( 3/7 + 3/5 )

x - 4/5 = 49/35

           x = 49/35 + 4/5

              x = 77/35

x - 7/35 = 4/5

             x = 4/5 + 7/35

                 x = 1

mình ko chắc chắn đâu

mình nghĩ mình làm sai

xin lỗi làm nhầm

a,

=85.35-85.27-35.85+35.27

=85.35+85.(-27)-35.85+35.27

=85[35+(-27)+(-35)]+35.27

=85.(-27)+35.27

=-85.27+35.27

=27.[(-85)+35]

=27.(-50)

=-1350

các câu còn lại cũng vậy

a, 85 x ( 35- 27 ) - 35 x ( 35 - 27 )

85 x 8 - 35 x 8

8 x ( 85 - 35 ) 

8 x 50 = 400

b, ( -45 ) x 69 + 30 x ( -45 ) +( -45)

( -45 ) x ( 69 + 30 + 1)

-45 x 100 = -4500

c , 26 + 7 x ( 4 - 12 )

26 + 7 x ( - 8 )

26 + ( -56 )=(- 30)

d , 127 - 18 x ( 5 + 6 )

127 - 18 x 11

127 - 180 + 18

-53 + 18 = - 35

a.85x(35-27)-35x(85-27)

=85x8-35x58

=680-2030

=(-1350)

b.(-45)x69+30x(-45)+(-45)

=(-3105)+(-1350)+(-45)

=1800+(-45)

=1755

c.26+7x(4-12)

=26+7x(-8)

=26+(-56)

=(-30)

d.127-18x(5+6)

=127-18x11

=127-198

=(-71)

li-ke cho mình nha bạn